What Is a Hunger Headache?

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A hunger headache, also called a fasting headache, is triggered by not eating. It may come on suddenly or slowly, and the pain is constant and occurs on both sides of your head. A hunger headache generally resolves within 72 hours after eating.

Woman with headache rubbing forehead

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Causes

Blood Sugar Levels

Low blood sugar, also known as hypoglycemia, is when the body’s glucose levels are 70 milligrams per deciliter (mg/dL) or below. When this occurs, people may experience symptoms such as dizziness, shakiness, and confusion.

Hypoglycemia often occurs in people with diabetes, especially those with type 1 diabetes, but having low blood sugar does not mean you have diabetes. People with nondiabetic hypoglycemia are generally recommended to go no more than three hours between meals.

One study demonstrated that hypoglycemic patients are more likely to be hungry and have headaches, compared with non-hypoglycemic patients.

Type 1 diabetes is when the pancreas cannot produce insulin, while type 2 diabetes occurs when the body has trouble responding properly to insulin and regulating glucose levels. If someone with type 2 diabetes takes too much insulin, they may experience low blood sugar.

Dehydration

Headache is a known symptom of dehydration, when your body does not get enough water. Water is necessary for the body to perform basic functions, such as cellular metabolism. It also helps the body process food by contributing to the cycle of energy necessary for your body to sustain basic functions.

When your body does not perform basic functions at optimal levels, it will start to conserve energy. This can result in the constriction (narrowing) of blood vessels, which may lead to a headache.

Caffeine Withdrawal

Regular consumption of caffeine leads to the dilation (expansion) of blood vessels. When the body does not get the caffeine it's used to getting, blood vessels may shrink and lead to a caffeine-withdrawal headache. Disruption in caffeine intake if you regularly consume two or more cups of coffee per day can lead to this type of headache.

Symptoms

A hunger headache causes a squeezing or pulsating feeling, rather than a throbbing headache. You will feel the pain on both sides of your head. It may feel like you have a vise around your head.

The pain is usually mild or moderate. You may feel it at your temples or the back of your head and neck.

Treatment

If you experience low blood sugar, follow the 15–15 rule: Consume 15 milligrams of carbohydrates, wait 15 minutes, and measure your blood sugar level again. If your blood sugar is still below 70 mg/dL, repeat the steps until your blood sugar reaches 70 mg/dL.

If your blood sugar gets low often, you should carry healthy snacks with you at all times. Apply the 15–15 rule to get your blood sugar back to normal when it gets low. These snacks should contain carbohydrates. An alternative is to carry glucose tablets, which are chewable supplements that quickly increase your blood sugar.

The treatment for dehydration headaches is to increase your water intake. You can do this by carrying around a large water bottle, giving you easy access to water as well as being a visual reminder to drink water. You can even track your water intake with apps on your phone.

If you experience a caffeine-withdrawal headache, it is important to stay hydrated and taper your caffeine intake. You can also try drinking low-caffeine beverages, such as teas with low or no caffeine and decaf options.

If you have type 2 diabetes, make sure to wait at least 15 minutes after a meal before testing your blood sugar to make sure you do not inject too much insulin and cause hypoglycemia.

Prevention

Avoiding headaches caused by low blood sugar can be achieved by eating healthy foods on a regular basis.

To avoid dehydration headaches, increase your water intake. If you do not like the lack of flavor in water, you may want to consider adding sugar-free flavored drops to your water.

To avoid caffeine withdrawal headaches, avoid consuming large amounts of caffeine. Experiment with low- or no-caffeine versions of your favorite drinks, or try something new. Drinking water can also help prevent caffeine headaches.

A Word From Verywell

Experiencing hunger headaches can significantly impact your quality of life, affecting your ability to function in your daily activities. Luckily, hunger headaches can sometimes be prevented when you anticipate their triggers and plan ahead by eating healthy, drinking plenty of water, and reducing caffeine intake. Though it could take some getting used to, the routine is generally easy to build into most lifestyles and can drastically improve your quality of life.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition (beta version). Cephalalgia. 2013 Jul;33(9):629-808. doi:10.1177/0333102413485658

  2. Kalra S, Mukherjee JJ, Venkataraman S, et al. Hypoglycemia: The neglected complication. Indian J Endocrinol Metab. 2013;17(5):819-834. doi:10.4103/2230-8210.117219

  3. Shaheen NA, Alqahtani AA, Assiri H, Alkhodair R, Hussein MA. Public knowledge of dehydration and fluid intake practices: variation by participants' characteristicsBMC Public Health. 2018;18(1):1346. doi:10.1186/s12889-018-6252-5

  4. American Diabetes Association. Hypoglycemia (low blood sugar).

  5. American Migraine Foundation. Understanding caffeine headaches